Lighting fixture



Patented Jan. 6, i948 LIGHTING FIXTURE Robert G. Nordquist, Glen Ellyn, Patent License Corporation,

corporation of Illinois Application July 30, 1943, Serial No. 496,748 ljs claims. (c1. 24o-51.11)

This invention has to do with lighting fixtures of the controlled beam type used in providing intensified illumination over certain vpredetermined areas within passenger vehicles and other enclosures, A

The object of the inventionis to provide an improved lighting fixture of thetype described in -which an elongated source of light, such as a uorescenttube, is used in conjunction with a correspondingly elongated light transmitting panel, and in which the spread of the more intensified portions of the light emanating from the fixture is restricted in the direction of elongation of the source whereby to eliminate endwise glare from the fixture when viewed from a point beyond the end of the same.

While the foregoing statements are indicative in a general way of the nature of the invention, other more specific objects and advantages will be apparent to those skilled in the art upon a full understanding of the construction, arrangement and function of the parts entering into the improved fixture.

. Two embodiments of the invention are presented herein by way of exemplincation, but it will of course be understood that the invention is susceptible of incorporation in other structurally modified forms coming equally within the scope of the appended claims.

In the accompanying drawing:

Fig. 1 is a face view of a fixture constructed in accordance with the invention;

Fig. 2 ls a fragmentary vertical longitudinal section through the center of the fixture, taken on the line 2 2 of Fig. l;

Fig. 3 is a vertical transverse section, taken on the line 3 3 of Fig. 1;

Fig. 4 is a fragmentary detail section through the light transmitting panel of the fixture, showing diagrammatically the manner in which those rays which are permitted to pass through the transversely extending lens sections of the panel are condensed and the manner in which other rays are )prevented from passing through the lens sections;

Fig. 5 is a fragmentary face view of a row of the xtures arranged end to end;

Fig. 6 is a fragmentary s ide view of the same; and v Fig. Iris a fragmentary detail section which Ill., assign-lor to Chicago, Ill., a

corresponds to Fig. 4 but shows a modified form of the invention,

The xture shown in Figs. 1 to 4 inclusive comprises an elongated downwardly opening casing Ill which is made of sheet metal or other suitable material. The casing is adapted to be mounted in an over-head position within a vehicle or other enclosure. The casing contains two flucrescent tubes II which extend longitudinally of the casing in spaced parallel relation to each other. The bottom of the casing is tted with a correspondingly elongated light transmitting panel I2, which panel isheld in place by a frame I3. One side of the frame I 3is hinged to one of the lower edges of the casing at I4, while the other side of the frame is detachablysecured to the opposite edge of the casing at I5.

The inventionv resides primarily in the constructionvof the light transmitting panel I2 and the manner in which the same is utilized to control within certain limits the endwise spread of the rays of light passing vthrough it.

The panel I 2 is preferably of shallow U-shaped cross section. It is preferably made of glass but it may be made of any other suitable light transmitting material. The side portions I6 of the panel are preferably enameled, etched or otherwise treated to render them light diffusing, while the relatively wide center portion Il is divided into a plurality of narrow transversely extending clear lens sections I8 through which rays of light from the tubes Il are adapted to pass to provide the intensied illumination desired.

The inner surface I9 of the centervportion Ii of the panel is substantially flat at the locations o f the lens-sections I8 and is provided with upwardly tapering louver-like ribs 20 between the sections, which ribs are enameled, etched or otherwise treated to block olf beyond certain angles longitudinally of the tubeslI slanting rays of light which would otherwise enter the sections. The outer surface 2 I of the panel is characterized by convex lens formations-22 tions I8 throughout the width of the center portion I1 of the panel. The lens formations 22 serve to` condense the entering rays in a direction longitudinally of the tubes I I and thus confine within certain angles (indicated at 23 in Fig. 4 for one of the sections) the spread of the rays upon leaving the sections.

which span the sec- By employing the above described panel construction the longitudinal spread of the more intensified light rays leaving the panel can be con'- trolled within any desired limit at all points throughout the length of the panel, with the result that endwise glare from the xture can in large measure be eliminated.

A trough-shaped reflector 24 is preferably positioned in the casing lil behind the tubes li to increase the efficiency of the fixture and at the same time control the lateral spread of the beam or beams emanating therefrom. The clear center portion I1 of the panel provides the intensified illumination desired over certain predetermined areas, while the light diffusing side portions IB provide relatively subdued illumination outside of such areas.

While two fluorescent tubes il are employed in the particular fixture herein used t'o exemplify the invention it will of course be understood that a single tube might be employed. It will also be understood that the elongated source of light, instead of being produced with one or more ucrescent tubes, might be produced with one or more rows of closely arranged individual bulbs, and that in some conceivable embodiments of the invention a single point source of light might y even be utilized.

While the panel i2 is preferably formed inone piece as an integral structure it might of course be formed in a plurality of separate pieces with the division lines located for instance at the centers of the ribs 20.

In Figs. 5 and 6 a lighting arrangement is shown in which a series Of the xtures 25, 28 and 21 are arranged in-a row in end to end relation to produce what is in effect one continuous lixture.

In the modification shown in Fig. 7 the transversely extending lens sections 28 of the panel 29 are formed as separate pieces. The ribs employed in the rst described embodiment for blocking olf beyond certainv angles longitudinally of the tubes rays which would otherwise enter the sections are omitted and thin louver strips 30 are instead positioned between the sections. The strips 30, which may be made of opaque, translucent, or highly reflective material, or which may be merely coatings or polishedl surfaces on the side faces of the sections, serve to box in the rays entering the sections beyond certain angles longitudinally of the tubes, whereby to prevent too great a longitudinal spread of the rays leaving each of the sections. The sections 28 may be rigidly connected together through the strips 30, if desired, whereby to form Iof the same an integral structure.

I claim: Y

l. In a lighting fixture of the type described, an elongated source of light, and a panel which is divided into a plurality of narrow transversely extending sections through which rays of light from the source pass, each of said sections being provided with means projecting a, substantial extent internally of the panel for blocking off beyond certain angles longitudinally of the source rays which would otherwise enter the sections, and each of said sections being also provided with convex lens formations for condensing the entering rays longitudinally of the source whereby t0 conilne within certain angles the spread of the rays upon leaving the sections, and each of said lens formations being centered with respect to each fysection with its axis normal to the face of the section.

2. In a lighting xture of the type describedjan elongated source of light, and a panel which is divided into a plurality of narrow transversely extending sections through which rays of light from the source pass, the inner surface of the panel being substantially at at the locations of the sections and being` provided with upstanding ribs between the sections which serve to block ofi be yond certain angles longitudinally lof the source rays which would otherwise enter the sections, and the outer surface of the panel being provided with convex lens formations spanning the sections in centered and normal relation to the latter. which formations serve to condense the entering rays longitudinally of the source and thus conne within certain angles the spread o f the rays upon leaving the sections.

3. In a lighting fixture of the type described, an elongated casing, one or more uorescent tubes arranged longitudinally within the casing, and

an elongated panel of shallow outwardly convex trough-shaped formation attached to the casing in front of the tube or tubes. said panel being characterized by a center portion and two side portions, and said center portion being divided into a plurality of narrow transversely extending sections through which rays of light from the tube or tubes pass, the outer surfaces of the side portions of the panel being rendered light diffusing, and the inner surface of the center portion of the panel being substantially flat at the locations of the sections and being provided with upstanding ribs between the sections which serve to v block oil beyond certain angles longitudinally of' i the tube or tube rays which would otherwise enter the sections, and the outer surface of the center portion of the panel being provided with convex lens formations spanning the sections in centered and normal relation to the latter, which formations serve to condense the entering rays longitudinally of the tube or tubes and thus conne within certain angles the spread of the rays upon leaving the sections.

4. In a lighting fixture of the type described, a source of light and a light transmissive panel adjacent said source having a plurality of relatively narrow sections extending transversely of the source and arranged in side-by-side succession longitudinally of the source, each of said sections comprising a transparent condensing lens portion and a non-transparent light blocking element, said lens portion being rounded on the outer surface of each of the sections opposite the source and having uniform light condensing action along its transversely extending dimension, said light blocking element being disposed substantially in its entirety internally of said outer panel surface and to one side of the lens portion to prevent emanation of certain rays angled longitudinally of the source, said outer panelsurface being ribbed longitudinally of the source by said rounded lens portions and being free of other ex ternal projections. V

5. In a lighting fixture of the type described, an elongated source of light and an elongated light transmissive panel adjacent said source having a plurality of relatively narrow sections extending transversely of the source and arranged in side-byfside succession longitudinally of the source, each of Ysaid sections comprising a transparent condensing lens portion and a non-transparent light blocking element, said lens portion being rounded on the outer surface of each of the sections opposite the source to condense entering rays longitudinally of the source, said lens portions having uniform light condensing action I transversely of the source, said light blocking element being disposed substantially in its entirety internally of said outer panel surface and to one side of the lens portion to prevent emanation of 5 certain rays angled longitudinally from the source, said outer panel surface being ribbed longitudinally `of the source by said rounded lens portions and being free of other external Projections.

ROBERT G. NORDQUIST.

REFERENCES CITED The following references are oi' record in the le of this patent:

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